Which of the following is not a luminous object(A). Sun(B). Moon(C). Bulb(D). Candle

The answer is (D) Candle.

Luminous objects are objects that produce their own light.

(A) Sun is a luminous object because it emits its own light due to nuclear fusion in its core.
(B) Moon is not a luminous object; it reflects the light of the Sun, so it appears bright in the night sky but does not produce its own light.
(C) Bulb is a luminous object because it emits light when electricity passes through it and heats up the filament.
(D) Candle is not a luminous object; it produces light by burning a wick, which generates a flame that emits light and heat, but the candle itself does not generate light independently.